My candidate would be volcanic eruption.
I say this because a friend of mine from our time at Keesler Airforce Base later ran the meteorological computers at Tinker Airforce base for a decade and a half.
The Ozone layer thins when volcanoes erupt chlorine compounds into the upper atmosphere.
Since we can’t stop volcanoes the old fashioned way of throwing a virgin in maybe we can stop them by throwing the politicians in? I’m not sure if this would work but I still think we should try this again and again until we have good results.